1. Field of the Invention
This invention relates to yellow to blue bisanil disperse dyes prepared from diaminomaleonitrile.
2. Description of the Prior Art
Monocondensation products of diaminomaleonitrile with various aldehydes are known in the art. Onoda in Nippon Nogeikagaku Kaishi, 36 (2), 167-72 (1962) discloses yellow monocondensation products of diaminomaleonitrile with aldehydes; the products are of the formula EQU Ar--CH=N--C(CN)=C(CN)--NH.sub.2
wherein Ar is either phenyl, p-dimethylaminophenyl or furfuryl. Robertson and Vaughan in J. Am. Chem. Soc., 80, 2691 (1958) disclose yellow monocondensation products of such formula wherein Ar is either p-hydroxyphenyl, p-nitrophenyl or cinnamyl. Reported attempts to introduce a second mole of the same aldehyde appear to have been unsuccessful and attempts to introduce a second mole of a different aldehyde with monoanil (Schiff base) resulted in displacement of the aldehyde residue of the original derivative. Such displacement facilely occurred when the second aldehyde possessed a carbonyl carbon atom of greater electron deficiency than the original aldehyde; for example, p-nitrobenzaldehyde &gt; benzaldehyde &gt; p-hydroxybenzaldehyde (decreasing order of facility of displacement). Hinkel et al. in J. Chem. Soc., 1432 (1937) disclose yellow monocondensation products of such formula wherein Ar is either phenyl, p-anisyl, salicyl or m-bromosalicyl. None of the aforementioned references discloses that the monoadducts of diaminomaleonitrile and aldehydes are useful as dyestuffs for synthetic fibers, especially polyester fibers.
U.S. Pat. No. 2,200,689 discloses heterocyclic pyrazinocyanine pigment dyestuffs which are obtainable by condensing diaminomaleonitrile with 1,2-dicarbonyl compounds, such as diacetyl, glyoxal, benzil, ortho-benzoquinone, acenaphthenequinones, thionaphthenequinones, phenanthrenequinones and aceanthrenequinones, at about 100.degree.-300.degree. C. in the presence of a solvent, pyridine and a metal salt. They are described as having good fastness properties.
Linstead et al. in J. Chem. Soc., 911 (1937) describe a variety of phthalocyanine-type pigments which vary in color from blue to green with increasing molecular weight; they are prepared by treatment of 2,3-dicyanopyrazines of the formula ##STR1## wherein R is H, CH.sub.3 or phenyl with copper salts. The 2,3-dicyanopyrazines can be prepared by condensation of diaminomaleonitrile with, respectively, glyoxal, diacetyl and benzil.